Point-of-Care Testing-Based Supplementary Parameters for the Early Identification of Reduced Kidney Function in Adults

Research

Abstract

Introduction: Declining kidney function often goes undetected due to limited access to conventional laboratory testing. Pos Pembinaan Terpadu (Posbindu) provides simple point-of-care testing (POCT)–based laboratory examinations that can serve as screening parameters for early detection of kidney function impairment. This study aimed to assess the ability of POCT parameters used in Posbindu to predict decreased kidney function in adults. Methods: A cross-sectional study was conducted in five administrative regions of Jakarta from July 2024 to June 2025, involving participants who met the inclusion criteria. The variables included simple POCT parameters such as blood glucose, hemoglobin, hematocrit, uric acid, and lipid profile. Kidney function was determined using the estimated glomerular filtration rate (eGFR; CKD-EPI) with cutoffs of < 80 mL/min/1.73 m² and < 60 mL/min/1.73 m². Spearman correlation analysis was performed to evaluate initial associations, followed by receiver operating characteristic (ROC) analysis to assess discriminatory ability. Confidence intervals were calculated using the Fieller, Hartley, and Pearson methods. Results: Among the 235 respondents, 99 had an eGFR < 80 mL/min/1.73 m², and 18 had an eGFR < 60 mL/min/1.73 m². ROC analysis revealed variability in the predictive ability of the parameters for both kidney function categories: hemoglobin (area under the curve/AUC 0.494 vs. 0.524), fasting blood glucose (AUC 0.549 vs. 0.601), total cholesterol (AUC 0.562 vs. 0.503), HDL (AUC 0.512 vs. 0.457), and LDL (AUC 0.535 vs. 0.427), all of which were not significant (p > 0.05). The parameters with better predictive ability were uric acid (AUC 0.591, p = 0.017 at eGFR < 80; AUC 0.681, p = 0.011 at eGFR < 60 mL/min/1.73 m2, followed by triglycerides, which showed a significant association only at eGFR < 60 (AUC 0.663, p = 0.021) but not at eGFR < 80 (AUC 0.561, p = 0.109). Uric acid demonstrated the strongest and most consistent discriminatory ability, supported by biological plausibility involving oxidative stress, endothelial dysfunction, and afferent arteriolar changes that accelerate glomerular filtration decline. Triglycerides showed a complementary but more limited role, consistent with lipid-mediated kidney injury that typically becomes more apparent at more advanced stages of function decline. Given the cross-sectional design, we could not establish causal or temporal relationships, including the possibility of reverse causality. Conclusion: Uric acid demonstrated the most consistent discriminatory ability for declining kidney function at both the mild and moderate-to-severe decline thresholds, whereas triglycerides showed significant discriminatory ability only at the moderate-tosevere threshold, supporting the potential of both as substitute POCT-based parameters for the early screening of declining kidney function in the adult population.